78878025 divided by 639 
The aim is to understand the frequency of 639 in 78878025.

Moving on to step 1:
7 divided by 639 is 0 with a remainder of 7.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Bring next digit (8) of the dividend behind the 7 and repeat the process: 78 / 639

Advancing to step 2:
The number 639 fits into 78 0 times, leaving a remainder of 78.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 78 and we're left with 78.
Bring next digit (8) of the dividend behind the 78 and repeat the process: 788 / 639

Step 3:
639 goes into 788 1 times with a remainder of 149.
The next digit of our result is 1. 
Result so far: 1.0
The remainder is 149 after subtracting 639 from 788.
Append the next digit (7) from the dividend to 149 and continue with: 1497 / 639

Going ahead to step 4:
1497 divided by 639 is 2 with a remainder of 219.
The next digit of our result is 2. 
Result so far: 12.0
Subtract 1278 from 1497 to get 219.
Bring next digit (8) of the dividend behind the 219 and repeat the process: 2198 / 639

On to step 5:
If we divide 2198 by 639, we get 3 and a remainder of 281.
Write down 3 as next digit of the result. 
Result so far: 123.0
If we subtract 1917 from 2198, we get 281.
Append the next digit (0) from the dividend to 281 and continue with: 2810 / 639

On to step 6:
639 goes into 2810 4 times with a remainder of 254.
The number 4 becomes the next digit in our result. 
Result so far: 1234.0
Deduct 2556 from 2810 and we're left with 254.
Include the next digit (2) from the dividend after 254, then repeat: 2542 / 639

Advancing to step 7:
If we divide 2542 by 639, we get 3 and a remainder of 625.
The next digit of our result is 3. 
Result so far: 12343.0
Subtract 1917 from 2542 to get 625.
Grab the next digit (5) from the dividend, add it to 625, then carry on: 6255 / 639

Let's proceed to step 8:
When dividing 6255 by 639, we get 9 with a remainder of 504.
The number 9 becomes the next digit in our result. 
Result so far: 123439.0
If we subtract 5751 from 6255, we get 504.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5040, and continue the process.

On to step 9:
639 can be fit into 5040 7 times, resulting in a remainder of 567.
The next digit of our result is 7. 
Result so far: 123439.7
Subtract 4473 from 5040 to get 567.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5670, and continue the process.

On to step 10:
639 goes into 5670 8 times with a remainder of 558.
Record the quotient 8 as the next digit in the result. 
Result so far: 123439.78
The remainder is 558 after subtracting 5112 from 5670.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5580, and continue the process.

Advancing to step 11:
639 can be fit into 5580 8 times, resulting in a remainder of 468.
Record the quotient 8 as the next digit in the result. 
Result so far: 123439.788
If we take 5112 away from 5580, we end up with 468.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4680, and continue the process.

Our division results in 123439.788 with a remaining 0.0468.